Ashita no Joe tells the tale of a wandering orphan named Joe Yabuki. He falls into one of Tokyo's slums and gets into a fight with a local gang and his street fighting skills gets him the attention of a washed up alcoholic boxing trainer. Until he sticks up for Joe when the gang comes back to finish Joe, Joe decides to live with the trainer. Despite the trainer's generosity, Joe is still committing money making scams and lands him in prison. While serving time, he meets another boxer named Rikiishi Tooru who gets Joe interested in boxing. Upon release, Joe then pursues a boxing career.

[Source: Anime News Network]

Yabuki Joe is left downhearted and hopeless after a certain tragic event. In attempt to put the past behind him, Joe leaves the gym behind and begins wandering. On his travels he comes across the likes of Wolf Kanagushi and Goromaki Gondo, men who unintentionally fan the dying embers inside him, leading him to putting his wanderings to an end. His return home puts Joe back on the path to boxing, but unknown to himself and his trainer, he now suffers deep-set issues holding him back from fighting. In attempt to quell those issues, Carlos Rivera, a world renowned boxer is invited from Venezuela to help Joe recover.